Analgesic treatment with levomepromazine in acute myocardial infarction. A randomized clinical trial.

The efficacy of a non-narcotic analgesic is evaluated in a double-blind randomized series of patients with acute myocardial infarction (AMI). Levomepromazine or pethidine were given in 328 consecutive cases to 316 patients within 24 hours after the onset of symptoms. Levomepromazine, 12.5 mg, appeared as effective as pethidine, 50 mg, in the alleviation of pain, though the initial dose had to be higher. Nausea and vomiting were half as frequent in the levomepromazine group as in the pethidine group (p less than 0.001). The incidences of arrhythmias, lung oedema, hypotension and thromboembolic complications did not differ between the groups. The mortality rate in the first 4 weeks was 22% in the levomepromazine group and 37% in the pethidine group (p less than 0.005), and after one year 39 and 50% (p less than 0.05), respectively. It is concluded that levomepromazine is better tolerated than pethidine in AMI. This suggests that the present management of pain in AMI should be reconsidered.